Key cancer restricting regulator discovered

Toronto: Researchers have discovered a key regulator of energy metabolism in cancer cells that may play a crucial role in restricting cancer cell growth.

AMP-activated protein kinase (AMPK) acts as a "fuel gauge" in cells. It is turned on when it senses changes in energy levels, and helps to change metabolism when energy levels are low, such as during exercise or when fasting.

Researchers at McGill University found that AMPK also regulates cancer cell metabolism and can restrict cancer cell growth. The discovery was made by Russell Jones, assistant professor at McGill`s Goodman Cancer Research Centre.

Jones along with his team is the first to show that AMPK can act as a tumour suppressor in animals.

"Cancer is a disease in which cells lose their normal restraints on growth and start to divide uncontrollably. But, in order for cells to grow quickly they need enough energy to complete the task," Jones said in a statement.

"AMPK acts like the fuel gauge in your car - it lets the body know when energy levels are low, and stops cell growth until there is enough gas in the tank. We wanted to see if this fuel gauge could affect the development and progression of cancer.

"We found that mice lacking AMPK developed tumours faster, suggesting that AMPK is important for keeping tumour development in check, at least for some types of cancer," he said.

Researchers focused specifically on a type of blood cancer known as lymphoma. They discovered that the protein Myc, which is activated in more than half of all cancers, could promote lymphoma more rapidly when mice were deficient for AMPK.
One of the ways cancer cells support their enhanced rate of growth is by changing their metabolism, or how they generate energy. Cancer cells are different from normal cells in our body because they preferentially use sugar to fuel their growth.

Jones discovered that AMPK plays a specific role in restricting cancer cells` ability to use sugar to fuel their growth. "For cancer cells with low AMPK levels, their metabolism goes into overdrive," said Jones.